There exist thermal printers which perform printing using a thermal head. The thermal head may be a so-called line thermal head in which a number of heating elements are formed on a substrate so as to be arranged in a row, and the arrangement direction of the row of heating elements is perpendicular to a sheet transport direction.
A platen roller is disposed to oppose the thermal head, and the thermal head is biased against and comes into pressure contact with the platen roller. A sheet transport path on which sheets are transported is formed between the thermal head and the platen roller.
The sheet is printed by the thermal head while being transported as the platen roller rotates.
In Patent Literature 1, the thermal head is fixed to a head frame. The head frame is provided in a thermal printer body via a head frame shaft, a coil spring, and the like which are provided in the head frame.